Does my engine sound OK?

[MikeDobbs]

Hey everyone,

So I just finished installing my new manifold and riser. This is the first time I have had the engine running since adjusting the valves as per the manual (the 3/4 of a turn past zero lash thing).

It definitely sounds much better to me than it did before the adjustment, but I do still hear a noticeable ticking/clicking/tapping noise. What I'd like to know is whether this is a reasonable noise for a Mercruiser 3.0lx circa 1998 with about 300 hours, or if this is a problem that I should be attending to. If you suspect the latter, I would welcome any suggestions as to what the problem might be or how I should proceed with fixing it.

Here's the video from today: I have it at idle for a bit at first, then bring it up to about 2000. The sound is quite a bit more pronounced at 2000 RPM than at idle

 

[MikeDobbs]

For reference, here'e the video from before the valve adjustment

 

[MikeDobbs]

Sorry- don't know what happened there, but I lost the video for today's engine sound. Here is the current video:

 

[mfkadz]

It sounds better but there's still something wrong in there.

mike

 

[thumpar]

It sounds better but there's still something wrong in there.

mike

I agree.

 

[MikeDobbs]

Ideas- suggestions? Should I pull the rods? Or try adjusting the valves with it running?

 

[Eric 3.7LX Alpha 1]

Ya know... one thing it may be... The pushrods have a hole in them that send oil up to the rocker. I remember as a kid... my ol' man, taking his apart on his Olds or Buick, not sure.... on occasion, one of the pushrods would get blocked and not feed oil, and he had a noisy rocker. I know you said you tried to adjust with it running but was too messy.

Did you notice if all of the rockers were getting oil?

He would remove the pushrod and pass a some mechanic's wire thru it to clean the passage. Quiet afterwards.... Just an idea to check...

Pull the cover off and run it long enough to inspect all of the rockers are getting oil.

 

[MikeDobbs]

OK Eric- I'll try that. Unfortunately right now I can't get it started again : (

Hoping I just flooded it I guess? Ran well for about 15-20 minutes earlier. Went back out to start it about a half hour later, and she just cranks and cranks...

 

[MikeDobbs]

OK well- turns out I just flooded it. Got the engine running again- pulled all the cabling off the rocker arm cover, and ran it with the cover off. I can see oil pumping up through all the pushrods- so that's not the issue.

I tried setting the lash while running (back it out until you hear noise, then tighten till you don't- 3/4 turn past there), but I can't hear anything with the engine running no matter how much I back out the nut it seems. So I went through and re-adjusted all the valves with the engine off. I'll see if that helps any- otherwise, I'm not sure what else to do...

 

[flipbro]

Next time you flood it hold the throttle wide open and crank it. Don't pump just wide open till it fires.Mike that noise does not sound good.If it were me id be pulling the motor and tearing it down to investigate.If youve rulled out bent pushrod or collapsed lifter I would start leaning towards a bad rod bearing to a broken piston skirt..

 

[MikeDobbs]

If youve rulled out bent pushrod or collapsed lifter .

I'm not sure I have ruled out either. Is spinning the pushrods enough to rule out a bent one? What is a collapsed lifter- and how would I tell if I have one? I actually tried re-adjusting the valves today, but now it sounds funny when cranking and won't start. Guess I'll have to go through that again tomorrow...

 

[flipbro]

Pull the push rods out mark were they come out and be sure to put them back in were they came out of. Roll them on a flat surface if bent you will notice. Now look at the hydraulic lifters were the push rod sites there is a retaining clip are the centers tightly seated against the clip.Do a google search and read up.

 

[NHGuy]

You can also use a long screwdriver or ratchet extension as a stethoscope. When it's running try holding one end on different suspected areas of the engine and then rest the outer end on the bone in front of your ear. Til you find the noise. Then start checking parts.
Obviously be extremely careful not to contact any moving parts. If you do it's potential injury, death,or damage. Be aware, don't take chances. Only check what is safe to reach.

 

[MikeDobbs]

NHGuy- I actually have an automotive stethoscope, and that's the craziest thing- when I use it I can't seem to find the offending noise. Everything sounds sort of a normal amount of moving engine part noise. I hear tapping- but I hear i everywhere- so I can't localize it to any particular region.

flipbro- I'll try to search what you are referring to. Are you saying the lifters are under the push rods? Those holes are pretty small- I'm not sure I'll be able to see anything inside them (the push rods are about 10 inches long, and the holes can't be more than 3/8 inch around...

 

[flipbro]

Mike im not real familier with the 3.0. Im more of a v8 guy but the valve trains are some what similar. On your engine I believe there is a tin cover that you remove on side of engine to get to the hydrolic lifters

 

[MikeDobbs]

Mike im not real familier with the 3.0. Im more of a v8 guy but the valve trains are some what similar. On your engine I believe there is a tin cover that you remove on side of engine to get to the hydrolic lifters

Hmmmmmm- that's interesting- I was just going to say that I'm not even sure I have lifters on this engine- the holes the pushrods go through are not even a half inch wide- probably less- I don't see how I could get anything into or out of them.

I'll look into this plate on the side idea- if that's the case, might not be such a hassle to access them if they're damaged.


I did go back and readjust the valves using the advice you gave me and it started right back up. While I was in there, I pulled every push rod this time and checked for straightness against a piece of glass- they all looked good. No mushrooming or signs of wear or damage on the ends either.

Here's a video of how the engine sounds now... looking for feedback once again on whether this is a reasonable amount of sound for an older engine like this (1998) or the harbinger of serious problems. To put this another way- can I enjoy the boat for the summer and deal with this later (or never)? My inclination at this point is to put some Seafoam (or similar) into the tank and some in the crankcase, and head to the water and just tool around at 15mph or so, and maybe it will take care of itself. Remember, the engine has been sitting idle for the last two years (at least).

Here's the vid- what do you guys think?

 

[MikeDobbs]

Of course I forgot the video again- here ya go!

 

[mfkadz]

There's still something going on in there. As far as running it.... Sure. it could do that forever. If you notice a change it could be a sign. If it fails without notice the recovery from that could be costly.

mike

 

[MikeDobbs]

I'd like to give an update on what I've seen the rest of the day from this motor. I've been working on some other things around the boat (electrical, etc.) and periodically firing the engine up (because I've had trouble getting it started in the past).

So, since I did the most recent valve adjustment this engine fires up immediately EVERY time. When I say immediately, I mean it hardly cranks at all. Sounds like it gets to the first compression stroke of whatever piston is next and BOOM- she's running.

Some more information: She seems to idle pretty roughly for the first minute or so. I have to give it a little throttle to keep it from stalling (I think- I never actually let it stall, but it sure sounds like it's heading in that direction). Then, after running a short while she settles down into a comfortable idle with the throttle in Neutral position.

Finally, there's some bluish smoke in the exhaust upon start up. This quickly dissipates, and then she runs clean after that. When I say quickly, I mean less than 20 or 30 seconds.

So- does all of that tell you anything? I'm thinking that the immediate firing up may be a result of a better valve adjustment? I'm hoping anyway

Curious for any feedback about what if anything that tells you about the engine and how it's set up.

 

[mfkadz]

I would say you have the valve train as good as your going to get it. The fact it starts good now says there were issues with the cylinders sealing.

Now you just need to decide on that ticking.

mike